1. Field of the Invention
The present invention generally appertains to improvements in artists' painting technology and more particularly relates to a novel preformed canvas and to a novel canvas stretching assembly and to a new and novel articulated frame for stretching an artists' canvas and for use as a canvas supporting frame to provide a firm working surface for the artist.
2. Description of the Prior Art
In order that oil paintings can properly be done, it is first necessary to stretch the canvas on which the oil painting is to be made. Customarily, the canvas is cut, fitted and stretched across a rectangular wooden frame and tacked or stapled to the exterior edges of the frame. So that the canvas can be stretched under tension, the frame is usually expanded, primarily by structural means disposed at the corners of the frame.
Thus, in U.S. Pat. No. 55,579, the wooden strips of the frame are loosely connected at their corners by a tongue and groove arrangement and the frame is expanded by movement of the strips at the corners under the force of swivel buttons which bear against eccentric plates. The disadvantage of frames of this type lies in the fact that they are only slightly effective for a short period of time. The corners do not stay true in their relative movements and the mechanical forces tend to fail, thereby permitting the canvas to become slack.
Some attempts have been made to depart from movable corner constructions. Thus, in U.S. Pat. No. 2,760,299, inner and outer wooden frames are provided and the artists' water color paper, which could be a canvas, is stretched over the inner frame which is placed within the outer frame and mechanical forces in the form of bolt and nut assemblies are applied to move the inner frame toward the outer frame so as to exert a pull on the paper and stretch it.
Such an arrangement is unduly complicated and very time consuming and burdensome in use. In addition, this device, like the other devices, involves the use of a wooden frame which is not reliable for stretching purposes and which is not practically reusable. Also, such frame is heavy. The adjustable frame types, as disclosed in the foregoing patents, are cumbersome and structurally complicated.
Attempts have been made to provide stretching frames formed from metal. Thus, in U.S. Pat. No. 1,618,361, an expansible metal frame is disclosed. Such frame has upper and lower rigid rails connected by vertical stretching bars. The cloth is secured at its edges to the rails by a clamping means and the rails are spread apart to stretch the cloth by the spreading bars.
The main drawbacks with such a stretching frame are that the edges of the cloth are clamped by a complicated clamping arrangement to the bars and also by virtue of such clamping means care must be taken to ensure that the cloth edges do not tear under the strain of stretching. The cloth can only be stretched in two directions, namely, upwardly and downwardly. Additionally, the costs of the structure, especially the clamping arrangement, are prohibitive for artistic usage.